3.3 Halogenoalkanes

• Halogeno alkanes have one or more halogens attached to it.
• The longest carbon chain in a Halogeno alkane forms the last part of the name.
• The prefixes for the positions of the halogens in a Halogeno alkane are fluro, chloro, bromo, iodo, and RI odo.
• The numbers in the prefixes for the positions of the halogens in a Halogeno alkane state their positions on the carbon chain and must be in alphabetical order.
• Logen Joaquin's react with hydroxide ions via elimination using ethanol solvent.
• The solvent plays a significant role in deciding if a reaction is elimination or substitution.
• The OH- ions in the aqueous solvent act as a nucleophile, forming an alcohol instead of an alkene.
• Both alkene and alcohol can be formed when using a mixture of both solvents.
• The type of solvent used can determine whether a reaction is elimination or substitution.
• When sodium hydroxide reacts with a halogen or alkane, it can form an alkene if using ethanol as a solvent, but an alcohol if using water as a solvent.
• If the solvent is ethanol, the OH- acts as a base, forming an alkene.
• If the solvent is water, the OH- acts as a nucleophile, forming an alcohol.
• Chlorofluorocarbons (CFCs) are molecules that have had all their hydrogens replaced by chlorine and fluorine, used in refrigerants, propellants, deodorants, and are broken down in the atmosphere, causing a hole in the ozone layer.
• The reaction of a halogen and alkane with hydroxyl ions is different when using aqueous solvent instead of ethanol.
• Radicals are formed as UV breaks down CFCs, catalyzing the breakdown of ozone.
• Carbon chlorine bonds are broken down by UV, forming radicals that catalyze the breakdown of ozone.
• The propagation step involves the radical formed in the initiation step reacting with ozone to form a CLO intermediate and oxygen, which then reacts with more ozone to make oxygen and Cl.
• The termination step involves two radicals reacting together, forming CL2.
• CFCs are banned because they damage the ozone layer, despite their advantages.
• Hydrofluorocarbons (HFCS) are used as a safer alternative to CFCs.
• The initiation step involves UV breaking the CCL bonds, forming two radicals that will react with ozone.
• The CCL bonds are broken easiest, making CF bonds less likely to be broken because they are stronger.
• If there are more than one type of the same type of the halogen in a Halogeno alkane, the new prefix would die for to try three and tetra for four of them.
• The properties of Halogeno alkanes include an increase in boiling point as we go down the group due to the strength of the intermolecular force.
• The strength of the intermolecular force increases as we go down group seven due to the increase in the number of electrons in the halogens.
• The mechanism of the halogenation of alkenes involves a halogen atom breaking a bond and forming a new bond with the carbon, while a nucleophile, such as ammonia, adds a molecule to the carbon.
• The bond enthalpy of carbon-halogen bonds determines their reactivity, with the CI bond having the lowest bond enthalpy and being the easiest to break, making reactions with the CI bond more reactive.
• The product of the halogenation of alkenes is known as the nitrile.
• Alkynes are more reactive than alkenes because their carbon-carbon bonds are weaker and have less s character.
• In the halogenation of alkenes, a bond breaks and a new bond is formed between the carbon and CN-.
• The bond strength and polarity determine the reactivity of halogenation.
• Halogenation of alkenes can also occur with ammonia and ethanolic ammonia, producing a nitro product.
• A new bond is formed between the OH- and the carbon after the bond breaks.
• The conditions for a nucleophilic substitution reaction include warm aqueous sodium hydroxide and reflux.
• In the mechanism of a nucleophilic substitution reaction, a lone pair on the Delta positive nucleophile attacks the Delta positive carbon, replacing the hydrogen on the halogen or alkane.
• In a nucleophilic substitution reaction, a halogen or alkane reacts with a nucleophile to form an alcohol and a salt.
• The carbon in a nucleophilic substitution reaction breaks the weakest bond, which is always the carbon halogen bond.
• A new bond is formed between the OH- and the carbon after the bond breaks in a nucleophilic trials reaction.
• In a nucleophilic trials reaction, a cyanide will attack the Delta positive carbon and replace the hydrogen on the halogen or alkane.
• The product of a nucleophilic trials reaction is an alcohol and a salt.